major histocompatibility complex(MHC) class II molecules(HLA-DR, -D, -DQ) are immuoregulatory glycoproteins normally expressed on the surface of lymphocytes, marcrophages, and some endothelial cells, where they play a critical role in antigen
recognition and presentation. CD4(+) helper T cells recognize antigens only in the context of class II antigens on the surface of macrophages or antigen-presenting cells. The MHC class II molecules have also been demonstrated on various malignant
tumors. Although MHC class II expression had been demonstrate on some gastric adenocarcinomas, but little is known about its prognostic significance and its relationship to T cell infiltration.
Using immunohistochemistry in paraffin blocks, fifty cases of gastric adenocarcinoma were studied for HLA-DR expression of tumor cells and T cell infiltration arround the tumor. The conclusions are as follows.
1. the glandular differentiation was correlated with HLA-DR expression; the better differentiation showed the higher HLA-DR expression(p<0.05).
2. 2. HLA-DR expression was higher in expanding type tumor than infiltrative type(p<0.05).
3. The cases hiaving poor desmoplastic reaction revealed high HLA-DR expression(p<0.05).
4. Among the various inflammatory cells in stroma, heavy lymphocytic infiltration was associated with high expression of HLA-DR(p<0.05).
5. There was statistically significant correlation between T cell infiltration and HLA-DR expression(p<0.05).
6. High T cell population was associated the some good prognostic factors such as poor desmoplasia, expanding type tumor margin, low neural invasion, and low stage(p<0.05).
7. There was no specific correlation between HLA-DR exprexsion and other prognostic factors such as stage of tumor, lymph node status, lymphatic emboli, and vascular or neural invasion.
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